The CIA’s main reason for setting up shop in Benghazi was to uncover the plans of al Qaeda-linked extremists, yet its officers there detected no sign that terrorists were set to launch the deadly Sept. 11, 2012, attacks on the U.S. diplomatic mission and the agency’s own compound, a new House Intelligence Committee report shows.

Michael Morell, at the time the CIA’s deputy director and later its acting director, was asked during closed-door testimony before the House Permanent Select Committee on Intelligence why the agency established a base in Benghazi. The compound sat smack in the middle of the terrorist-infested city in eastern Libya, where militants had unleashed scores of attacks on Western targets all year.

“Sir, the focus of my officers in Benghazi was to try to penetrate the terrorist groups that were there so we could learn their plans, intentions and capabilities,” Mr. Morell answered.

Still, the House report released Friday, jointly written by Democrats and Republicans, concluded that the CIA’s inability to uncover plans to attack Americans that day did not present an intelligence failure.

“The IC [intelligence community] did not fail to provide specific, tactical warning of the attacks in Benghazi because it had no credible intelligence about the attacks before they began,” said the report.

After a two-year secret investigation, the report was endorsed by Reps. Mike Rogers, Michigan Republican and committee chairman, and C.A. Dutch Ruppersberger of Maryland, the committee’s ranking Democrat.

“I think Morell was trying to put a positive face on what was clearly a tragic failure,” said Bart Bechtel, a retired overseas CIA case officer. “While CIA is always trying to penetrate terrorist groups, you certainly would not want to highlight the location of your base of operations.

“Clearly, in my humble opinion, there was a breakdown in operational security and the vetting of potential targets,” Mr. Bechtel said. “I do not know who the CIA officers were in Benghazi, but I suspect they were not the most experienced that they should have been.”

Eight hours after extremists stormed the U.S. diplomatic mission, precise mortar fire hit the CIA base, with one round killing two security guards.

Larry Johnson, a former U.S. counterterrorism official and ex-CIA analyst, said it would have been impossible to set up a nighttime, urban mortar attack without prior planning of at least 24 hours, if not more. That would have been time enough, he said, for the intelligence community to smell out a plot.

“This was a colossal failure,” he said. “If that is what they were doing for more than 12 months, trying to penetrate terror groups, they failed.”

Former Navy SEALs Tyrone Woods and Glen Doherty died in the mortar attack on a rooftop as they tried to defend CIA case officers and rescue diplomats. U.S. Ambassador J. Christopher Stevens and his aide, Sean Smith, died at the scorched mission, which had been attacked first hours earlier, at 9:40 p.m.

Left murky by the House report is exactly what missions the CIA officers at the Benghazi base, or annex, had been trying to accomplish in addition to penetrating terrorist groups.

Various media outlets have reported that the CIA was actively involved in shipping arms through Libya to war-ravaged Syria. There, moderate fighters and radical Islamists are competing to bring down the regime of President Bashar Assad. The extremists include the Islamic State — also known by the acronyms ISIL and ISIS — which has conquered wide swaths of land and cities in Syria and Iraq.

The House report concludes that the CIA did not ship weapons. It said officers were collecting intelligence on “foreign entities that were themselves collecting weapons in Libya and facilitating their passage to Syria.”

Inaccurate ‘talking points’

In a released transcript, Rep. Devin Nunes, a California Republican who will succeed Mr. Rogers as committee chairman, asks Mr. Morell about the CIA’s role. Much of Mr. Morell’s answer is censored.

At one point, he was interrupted by Mr. Rogers, who said that not everyone in the room that day held a high enough security clearance to hear what the CIA leader had to say about operations in Libya.

The report does not name the “foreign entities” moving weapons to Syria. Various Persian Gulf nations are competing against each other in Syria, betting on one side or the other with money and arms. Qatar, which supports Hamas, a U.S.-designated terrorist group supported by Iran, and the now-deposed Muslim Brotherhood in Egypt are said to have funded weapons for Islamists in Syria.

On other Benghazi issues, the House report reaffirms facts turned up in previous investigations, such as a Senate Select Committee on Intelligence probe released in January.

As did the Senate panel, the House report lists several al Qaeda-linked Islamic extremists groups and individuals who played a role in the twin Benghazi attacks. They include Ansar al-Sharia, al Qaeda in the Lands of the Islamic Maghreb, al Qaeda in the Arabian Peninsula and the Egyptian Muhammad Jamal Network.

The report further rebuts the White House’s election season public explanation that spontaneous demonstrators, spurred by an American anti-Muslim video, did the killings. At the time, President Obama’s re-election campaign had depicted al Qaeda as in retreat.

The Obama team’s erroneous public explanation was contained in CIA “talking points” that were written and rewritten over several days by the White House, State Department and CIA.

The CIA’s final version did not mention an American-made video, though the Obama administration, through then-U.S. Ambassador to the United Nations Susan E. Rice, clung to that explanation for days.

“The CIA never said that what happened in Benghazi was a result of the film,” Mr. Morell told the House committee, released transcripts show.

‘We did not pull our punches’

The driving force behind the video explanation was Ben Rhodes, then the White House National Security Council’s public relations strategist.

The House report noted an email from Mr. Rhodes describing a “PREP CALL” he planned to conduct with Ms. Rice the day before she appeared on the Sunday TV talks shows. He wrote to senior officials that the administration’s public statements should “underscore that these protests are rooted in an Internet video, and not a broader failure of policy.”

Ms. Rice cited the video as the reason demonstrators attacked in Benghazi.

The White House did not release the Rhodes email publicly until it was required to by a lawsuit filed by the watchdog group Judicial Watch.

The CIA, during streams of emails between it, State and the White House, whittled down what began as fairly accurate “talking points” into a set that blamed spontaneous demonstrations.

Mr. Morell himself took out the word “Islamic.” His public affairs office took out the word “al Qaeda” and added the word “demonstrations.”

While the editing was going on prior to Ms. Rice’s TV appearances, the CIA station chief in Tripoli sent a cable to headquarters in Langley, Virginia, saying there was no demonstration outside the mission.

Mr. Morell told the committee the inaccurate talking points did not represent the agency bowing to political pressure.

“I just want to take that off the table,” he said. “We did not pull our punches. We did not obfuscate in any way. We did not try to downplay the terrorist nature of the attack. And I can assure you of that.”

Mr. Morell retired from the agency and now works for a strategic communications firm led by former aides to Hillary Rodham Clinton.

Friday’s House report called the talking points “not fully accurate.”

Dwindling security

The report, while focused on the intelligence community, marked another damning assessment of the State Department, then led by Mrs. Clinton.

First, it noted a series of written reports issued by the CIA to the White House, State Department and other agencies warning of a deteriorating and dangerous security environment in Benghazi as Islamic extremists attacked Western targets one by one.

A House Committee on Oversight and Government Reform investigation turned up witnesses who said the State Department blocked Stevens’ requests for more diplomatic security officers and discouraged him from seeking military help. A time line shows that as extremists stepped up their attacks in Benghazi, American security ranks decreased.

Five diplomatic security agents were assigned to the ambassador, and they did not feel confident. The House report reveals that they themselves did not believe they were prepared to defend Stevens.

CIA officers “testified that State Department DS [diplomatic security] agents repeatedly stated they felt ill-equipped and ill-trained to contend with the threat environment in Benghazi. The DS agents knew well before the attacks that they could not defend [the mission] against an armed assault.”

The House intelligence document does not paint a flattering picture of the five diplomatic security guards’ performance once the attack started, with militants invading offices and torching villas. It says that when a rescue team arrived at the mission from the CIA annex, only one security officer was armed.

Not a shot fired

Back at the annex, now under attack, only one rescued DS agent joined the former SEALs on the roof. The others huddled with case officers inside.

The Senate’s report said those same diplomatic guards, who had been issued assault rifles, never fired a shot at the mission while it was under attack.

After the Senate report was issued, Douglas Frantz, the State Department’s assistant secretary for public affairs, defended the guards.

“We’re concerned by the perception the DS agents were not doing their job, when, in fact, at great risk, they tried to save Ambassador Stevens and Sean Smith,” Mr. Frantz told The Washington Times. “They tried to go back into the building to find them in the smoke. The DS agents were grossly outnumbered at that point, and they are trained not to make these situations worse.

“The thinking was, if they went in there guns ablaze, they would simply draw fire on themselves and reduce any chance they had of finding Sean Smith and Chris Stevens alive inside the building.”

The House intelligence report disclosed that the U.S. has identified 85 individuals who participated in the Benghazi attacks. One, Ahmed Abu Khattala, has been captured and brought to the U.S. for trial.

In his added remarks, Mr. Rogers castigated the State Department, saying it “dismissed repeated threat warnings and denied requests for additional security in eastern Libya, thereby placing U.S. personnel at unnecessary risk.”

He said Obama officials “perpetuated an inaccurate story that matched the administration’s misguided view that the United States was nearing a victory over al Qaeda.”

“The administration’s failed policies continue to undermine the national security interests of the United States,” Mr. Rogers said.